many among the tens of thousands of demonstrators still jammed into tahrir square repeat that they will not leave until president mubarak steps down. they see themselves on a mission, where turning back is simply not an option. cnn's ivan watson spoke with some of them about their bravery and defiance. >> reporter: men barricade in tahrir square. cold, battle scarred and filthy, they fought and bled to protect the symbol of egyptian defiance. it was raining. it was cold here last night. >> yes, yes, yes, yes. and stand and tired and we will continue forever until that system removed. >> reporter: abdul suffered head wounds during last wednesday's furious battle between opposition demonstrators and president hosni mubarak's supporters. how did you feel fighting other